Waste minimization filters

Waste Minimization and Disposal. CFF systems minimize disposal costs (e.g., when ceramic filters are used) whereas in diatomaceous (DE) pre-coat filtration substantial waste disposal costs may be incurred, particularly if the DE is contaminated with toxic organics. Currently, in many applications, DE is disposed of in landfills. In future, however, this option may become less available forcing the industry to use cross-flow microfiltration technology or adopt other waste minimization measures. 

Does the process satisfy the principles of pollution prevention and waste minimization On the basis of the information provided by the vendor, scrubbed gases and solids are the only wastes produced other than arsenic. On the basis of the information provided by the vendor, scrubbed gases and metal are the only wastes produced other than arsenic. Yes. Wastes are metal, scrubbed offgases, arsenic residues, and contaminated filter media. The process satisfies the principles of pollution prevention. Although the process results in a large amount, relatively speaking, of secondary wastes, the amount is not excessive. 

Like primary filters, polishing filters must be taken off line for cleaning when flow rate deteriorates, differential pressure increases, or the body of the filter fills with solids. The emphasis in fundamental analysis of the filtration of brine is on the production of clear brine at a defined rate. The efficient removal of cake from the filter, however, is of equal importance. The removal of occluded brine from the cake for recovery or for waste minimization may also be necessary. Before cleaning, the brine inside the filter body is usually removed. This involves the use of compressed air to blow the brine back to its... 

At Hanford, for example, an evaporator is used to reduce the volume of waste entering the high-level storage tanks. The standard practice for ten years of evaporator operation was to use filtered river water, which was then sent for wastewater treatment after one use. This year, we made process modifications that allow the reuse of condensate water instead of the filtered river water. The expected dollar savings per year of operation is 3.1 million, and savings in filtered river water not used is 2.1 million gallons (over 8 million liters). We now require the consideration and incorporation of waste minimization features in the design process for all new facilities. 

Alternatively, the liquid removed in the centrifuge may be the waste material. The section on filter waste minimization and disposal (3.9.2) lists the relevant safety precautions. 

Filter aids should have low bulk density to minimize settling and aid good distribution on a filter-medium surface that may not be horizontal. They should also be porous and capable of forming a porous cake to minimize flow resistance, and they must be chemically inert to the filtrate. These characteristics are all found in the two most popular commercial filter aids diatomaceous silica (also called diatomite, or diatomaceous earth), which is an almost pure silica prepared from deposits of diatom skeletons and expanded perhte, particles of puffed lava that are principally aluminum alkali siheate. Cellulosic fibers (ground wood pulp) are sometimes used when siliceous materials cannot be used but are much more compressible. The use of other less effective aids (e.g., carbon and gypsum) may be justified in special cases. Sometimes a combination or carbon and diatomaceous silica permits adsorption in addition to filter-aid performance. Various other materials, such as salt, fine sand, starch, and precipitated calcium carbonate, are employed in specific industries where they represent either waste material or inexpensive alternatives to conventional filter aids. 

The environmental impact of the proposed GATS process appears to be minimal. All handling and processing of agent will be conducted indoors in sealed rooms that are vented through HEPA and carbon filters. Liquid and solid waste streams will be relatively small and manageable and will be subjected to hold-test-release procedures. 

Waste material snch as tank bottoms from crude oil storage tanks constitute a large percentage of refinery solid waste and pose a particularly difficult disposal problem due to the presence of heavy metals. Tank bottoms are comprised of heavy hydrocarbons, solids, water, rust, and scale. Minimization of tank bottoms is carried ont most cost-effectively through careful separation of the oil and water remaining in the tank bottom. Filters and centrifuges can also be used to recover the oil for recycling. 

Viable alternatives to cartridge filters include bag filters and metal mesh filters. Metal mesh filters are available in very fine micron sizes and they can be cleaned and reused. Since it is very important to minimize all wastes, the issue of mesh filter cleaning waste reuse or recycling would need to be addressed before switching to these filters. 

The most common method for cleaning the gun is to put a small amount of solvent into the pressure pot or cup gun, and clean the gun by spraying directly into the water curtain or dry filter of the spray booth. This is an unnecessary and expensive generation of waste. Both air emissions and waste paint are generated. In some states, notably California, regulations require that the paint operator spray gun cleaning solvents into a closed container so as to minimize VOC solvent emissions. This practice also allows recycling of the paint sprayed into the container (Joseph 1989). 

Precoating the filter medium prevents blinding of the medium with the product and will increase clarity. Filter aid must be an inert material, however, there are only a few cases where it cannot be used. For example, waste cells removed with filter aid cannot be reused as animal feed. Filter aid can be a significant cost, and therefore, optimization of the filtration process is necessary to minimize the addition of filter aid or precoat. Another possible detriment is that filter aid may also specifically absorb enzymes. 

SPILL CLEAN-UP Use a high-efficiency particulate arrestor (HEPA) filter to minimize amount of carcinogen immediately transfer used filters into plastic bags after removal place waste liquids in properly labeled containers for disposal the plastic bag should also be sealed and labeled. 

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